understanding uv maps, materials and textures
You have to add a texture to the material in the texture tab next to materials. Then select the mesh you want textured and bring up UV/Image Editor. To select the texture in UV/Image Editor you have to click the little picture button to bring up the drop down menu and then select the texture from there, while in edit mode, while the mesh you want textured is selected (not the object).

It's a little weird at first.